In recent years, the Internet has proliferated widely. Thus, users can access various information on sites run around the world and obtain the information. Accordingly, apparatuses capable of performing broadband access such as ADSL (Asymmetric Digital Subscriber Line) and FTTH (Fiber To The Home) have also been widely used at a rapid pace.
IEEE Std 802.3ah (registered trademark)—2004 (Non-Patent Literature 1) discloses one system of a passive optical network (PON) which is medium-sharing communication where a plurality of optical network units (ONUs) perform data transmission with an optical line terminal (OLT) by sharing an optical communication line. Specifically, there are defined EPON (Ethernet (registered trademark) PON) where all pieces of information including user information passing through the PON and control information for managing and operating the PON are communicated in Ethernet (registered trademark) frame format; and an access control protocol (MPCP (Multi-Point Control Protocol)) and an OAM (Operations Administration and Maintenance) protocol for EPON. By exchanging MPCP frames between the optical line terminal and the optical network units, joining, leaving, and upstream access multiple control of the optical network units, etc., are performed. In addition, Non-Patent Literature 1 describes a new-optical network unit registration method, a report indicating a bandwidth allocation request, and a gate indicating a transmission instruction, by MPCP messages.
Note that even in 10G-EPON which is standardized as IEEE 802.3av (registered trademark)—2009 as the next-generation technology of GE-PON (Giga Bit Ethernet (registered trademark) Passive Optical Network) which is EPON achieving a communication speed of 1 gigabit per second, i.e., EPON whose communication speed is equivalent to 10 gigabits per second, an access control protocol is premised on MPCP.